The Supreme Court will hear oral arguments today in a case court observers are calling a sequel to Citizens United.

In McCutcheon v. Federal Election Commission, justices will decide whether limits on donations from individuals to candidates and political parties are unconstitutional. The high court ruled in the 2010 Citizens United case that the government can’t restrict political expenditures from corporations or labor unions.

At issue in today’s case are “aggregate” campaign finance restrictions. In federal elections, individuals are limited to donating $48,600 to all federal candidates and $74,600 to political parties in a two-year election cycle, meaning the most any one person can donate to federal candidates and parties is $123,200.

While the aggregate limits have been raised over the years, the restrictions themselves stem from the 1976 case, Buckley v. Valeo, in which the court ruled that restrictions on individual contributions to political campaigns did not violate the First Amendment since the limits were necessary for the “integrity of our system of representative democracy.”

In today’s case, the lead plaintiff, Alabama businessman Shaun McCutcheon, has argued that donation limits violate free speech. If the court agrees, changes in aggregate limits would directly affect only a relatively small number of large donors.

According to a report from the Center for Public Integrity, using analysis from the Center for Responsive Politics, of the roughly 600 individuals who donated the maximum $46,200 to individual candidates, 45 percent gave mostly to Republicans, 37 percent mostly to Democrats, while 18 percent gave to both parties. Those donors gave about $34 million to 975 candidates, but another 1,700 people hit the top limit on donations to national party committees.

While decisions in cases with October oral arguments have been announced as early as November, the court has taken longer to decide those that are more complex, so a decision is likely several weeks away.